If certain subscribers of a radio communication system act as service providers and fulfill certain services for other subscribers of the communication system who act as service users, it is desirable for the other subscribers to reach the service providers at service call numbers that are not changed and known to the service users. These call numbers are ideally based on the type of service offered and, for example, may have a hierarchical structure or group allocations if the services of the different service providers are also divided into such groups.
The state of the art includes document EP 0,431,453. This document describes the allocation of such hierarchical or group-related object designations to service providers in the form of call numbers. In this case, a service call number is, if so requested, temporarily assigned to a service provider with an individual call number with the temporary service call number being adapted to the type of service provided by the service provider. The composition of the assigned call number makes it possible to directly conclude the activity currently being carried out.